Speech Development & Typical Errors

• customary production


  - when a child produces the sound correctly 50% of the time
• mastery


  - when a child produces the sound correctly usually 90% of the time across all word positions
• by age 5 (across all languages):


  - most children have mastered all consonants in their language

  - the percent consonants correct for a child is about 94%
• in US english by age 5:


  - have mastered most/all consonants except "th"

  - there is variability however

  - we also have new-er research suggesting older norms aren't as accurate as we thought
• older norms from Shriberg:


  - early, middle, late 8

  early: m, n, j, b, w, d, p, h

  middle: t, ng, k, g, f, v, ch, dʒ

  late: sh, ʒ, l, r, s, z, ð, θ, and clusters
• articulation errors


  - errors on individual sounds with the theory these are difficulties with the articulation/movements needed for that phoneme

  EX: lisp when producing /s/
• phonological errors


  - errors on groups of multiple sounds with the theory that these are difficulties with an underlying rule/reason for that whole group of sounds

  EX: 'k' and 'g' are similar in terms of where in the mouth they are produced and they're both stops; one is voiced and one is unvoiced

  - child might make an error by producing both toward the front of the mouth
• substitutions


  - child produces one phoneme instead of another

  EX: [red] becomes [wed]
• omissions


  - child leaves out a phoneme

  EX: [red] becomes [ed]
• distortions


  - child tries to produce a phoneme but the articulation isn't correct

  EX: "sad" with distorted /s/
• additions


  - child adds a phoneme where there shouldn't be one

  EX: /bred/ becomes /bəred/
• fronting


  - a sound that is usually made further in the back is produced more toward the front

  - velar fronting where velars are produced more toward the front of the mouth, usually as alveolars

  EX: "cat" becomes "tat"
• gliding


  - the 'r' and/or 'l' consonants produced more like the 'y' or 'w'

  EX: rabbit becomes "wabbit"
• stopping


  - sound that is not a stop in terms of manner of articulation is produced as a stop

  EX: "thick" becomes "tick"
• final consonant deletion


  - a final consonant of a syllable (or word) is deleted

  EX: cat becomes 'ca
• cluster redcution


  - when 2 consonants occur next to each other in a word and one is deleted

  EX: stop becomes top
• assimilation


  - changing the way one consonant is produced to make it more similar to other consonants in the same word
• labial assimilation


  - if a word has one bilabial consonant and one consonant that is not bilabial, the child will produce both sounds as bilabial

  EX: bat becomes "bab"